I've dealt with the double charged credit card thing with Walmart too. They charged me twice for my daughter's bed. It took three frustrating phone calls to sort out. I would just start buying my furniture at IKEA but they don't do deliveries or shipping.
One of my more recent bad experiences there was I stopped in to grab a few items and headed over to the express checkout line, because the other lines were all pretty busy. Anyhow, there were about four people in front of me, who I later realized were Wal-Mart employees, probably on their day off, who stopped in to pick up their paychecks. They weren't in line to purchase anything, they were in line to cash their checks. Apparently Wal-Mart employees can cash their checks at the cashier's registers - at least at this location they were. But to make matters worse, each of them was having the cashier deposit various amounts into specific accounts, and give them back certain amounts in cash. Because they were all getting so much cash off the cashier, twice she had to call over someone from the service desk to bring more money over to her register. This whole ordeal took a good 20+ minutes - which was really pissing me off because by that point I literally could not get out of the line because there were so many people behind me. I'm sorry, but they should be handling that shit at the customer service desk, or in the employee areas - not tying up paying customers and making them wait for all that. I wanted to complain to management so bad, but then I was worried I might get some people fired or in trouble.
We keep forgetting that those people don't work out of pleasure but necessity. I'm sure that if they found another more pleasant job, they would accept it right away and put aside their past. Of course, they have that job because us users pay and we'd appreciate to be given our rigorous respect, but they're humans, too, and they must be understood.